1. Field of the Invention
The present invention relates to a method and apparatus for providing a latching mechanism. In particular, but not exclusively, the present invention relates to a latching mechanism which can be used to determine when a braking member should or should not operate to retard rotation of a wheel of a castor secured to a vehicle or some other movable object.
2. The Prior Art
There are many instances known in which vehicles, or other such means of transportation, which are provided with one or more wheels should have their movement inhibited or prevented. A known way for achieving this is to provide a brake mechanism on one or more of the wheels. When motion of a vehicle or object is to be slowed or stopped, a signal is transmitted to a brake which is applied. The application of the brake retards rotation of a wheel.
Many different types of braking mechanism are known and the manner in which braking is achieved is often dependent upon the type of vehicle which is to be slowed or stopped.
It will be understood that embodiments of the present invention are generally applicable in the sense that they can be adapted to retard rotation of one or more wheels of any type of means of transportation or object which is provided with the facility to move. However, the present invention is particularly well suited to retarding rotation of at least one wheel of a castor for a shopping cart. Shopping carts, sometimes referred to as shopping trolleys, are well known and are provided by supermarkets or other retail establishments for shoppers to transport goods to be purchased in a very convenient manner. However, supermarkets are known to have a problem in that from time to time shopping carts may be removed from the premises by unauthorised personnel. Such removal costs retail businesses money to either replace or locate the trolleys and return them to a desired location.
Shopping carts are typically provided with four castors, each of which includes one or two wheels arranged to rotate about a common axis between forks. The forks are connected at a common point to the shopping cart.
Many methodologies and apparatus have been suggested in the past for avoiding the unauthorised removal of shopping carts. Some of these involve the inclusion of a braking assembly in at least one castor of the shopping cart. However, such braking assemblies can be costly to produce and are prone to failure from time to time. Another problem is that the environment in which the shopping cart operates is a relatively inhospitable environment. For example, shopping carts are often pushed or pulled over very uneven surfaces where a jarring motion may be transferred into the castor of the shopping trolley. This makes parts within the castor prone to failure and can cause a brake to invalidly deploy or unset.
Some known braking assemblies for wheels include a latch-like assembly in which a latch can be positioned in one of two positions. In a first position a brake operates to brake a wheel, thus retarding rotation of the wheel. In another position the brake is not applied. Many known latching assemblies are prone to failure either because of the environmental harshness noted above or because unauthorised personnel will attempt to disable the latch mechanism.
In this sense latching mechanisms per se are known for a whole host of different applications. As such these latching mechanisms are arranged to select one or more states. Once a state of a latch is selected, this determines operation of some machinery or other component parts in the apparatus where the latch mechanism is located. However, many types of latch mechanism are complex which makes them costly to produce and maintain or means that they are prone to failure. It will be understood that whilst embodiments of the present invention are described by way of example with respect to a latching mechanism applicable to select a braking state for a wheel of a shopping cart, embodiments of the present invention are generally applicable to circumstances where a latch mechanism is required to select one or more states of operation of particular equipment.
It is an aim of the present invention to at least partly mitigate the above-mentioned problems.
It is an aim of embodiments of the present invention to provide a latching mechanism in which a position of a latch member is determined using a very convenient method which is relatively cheap to produce and is not prone to error.
It is an aim of embodiments of the present invention to provide a method and apparatus for retarding rotation of a wheel of a castor of the type which can be secured to a vehicle or other object to be moved. Preferably the wheel is a wheel of a castor of a shopping trolley.